Stormwater Management Plans

Diehm & Sons provides stormwater design for residential, commercial, agricultural, and industrial projects, which is often incorporated into the subdivision or land development plan for the project. Additionally, we can perform stand-alone stormwater plans for construction not associated with a larger plan, such as a dwelling on an existing vacant lot, or for the addition of a secondary building. Our stormwater plans include surveying to provide a base map showing the location of the proposed improvements, providing a grading plan, a stormwater design, and an erosion control plan. We work with the landowner and builder to show the exact house footprint and grading preferences for the project, as well as submit the plan to the Municipality, Municipal Engineer, and Conservation District for review and approval.

Stormwater designs can utilize many different types of facilities. Diehm &Sons tailors the design of each project to be compatible with the preferences of the land owner, site constraints, and regulations. Facility options include traditional measures such as infiltration trenches and stormwater detention basins, and/or low impact measures, which are becoming more prevalent. Low impact development treats stormwater with smaller facilities and relies on infiltrating runoff back into the soils, and includes things like rain gardens, porous pavement, riparian buffer plantings and small underground infiltration facilities. Diehm & Sons determines the types of soils on the site and the potential for infiltration.

Erosion Control Plans

Erosion control plans provide temporary facilities to treat sediment-laden runoff from a construction site. These plans are often part of a stormwater plan, but can be stand alone. Diehm & Sons prepares the erosion control plan and submits the plan to the County Conservation District for review and approval. We also can perform NPDES permits for projects disturbing more than one acre, and work with a local wetland specialist to provide wetland delineations when needed.

Floodplain Studies

Diehm & Sons performs floodplain studies to determine the 100-year floodplain elevation associated with a watercourse. The floodplain study includes survey information to create a base map, drainage area and flow rate calculations, and floodplain elevation calculations. We can provide floodplain elevation certifications as requested for flood insurance purposes.

Highway Occupancy Permits

For projects with vehicular access onto a state roadway, Diehm & Sons can prepare the permit application, highway occupancy permit plans, and when needed, right-of-way plans for submission to PennDOT for review and approval.